Abstract
This work describes for the first time the integration of Dye Sensitized Solar Cell (DSSC) technology in biosensors and biomimetic materials, opening doors towards a new dimension of autonomous screening devices that may be used in point-of-care, with zero-power requirements. DSSCs are fabricated with a counter electrode (CE) of polypyrrole (PPy) that was made responsive to a specific protein by biomimetic material (BM) technology. Carcinogenic embryonic antigen (CEA) was selected as target protein. The resulting BM-PPy film acted as biomimetic artificial antibody for CEA. Rebinding of CEA into this film changed its intrinsic electrical properties and the subsequent electrical output of the DSSC using it as CE. The quantity of CEA in solution was deduced by I-V and electrochemical impedance spesctroscopy (EIS). Linear responses to CEA were observed down to 0.25 pg/mL, with 0.13 pg/mL detection limit. Control films of PPy (prepared without CEA in the electropolymerization step) confirmed the ability of the BM material to recognize the target protein. Accurate results were obtained in the analysis of urine samples. Further developments into this ground-breaking self-powered biosensor will display a huge impact in point-to-care medical applications, which may be extended to other fields of knowledge.
Highlights
Biosensors are an expanding field oftechnology[1,2]
It consisted in an imprinting stage where a thin-film of polymeric Py was produced in the presence of Carcinogenic embryonic antigen (CEA) and the biomimetic material was formed by removal of the CEA entrapped within the polymeric network
Py oxidises between +0.65 V and 0.90 V vs. SCE, but at higher potentials overoxidation of the deposited PPy film occurs, which is an irreversible process that leads to decreased conductivity[27]
Summary
Biosensors are an expanding field of (nano)technology[1,2] These devices moved chemical, biochemical and biological analyses from the conventional laboratory into the field. Electrochemical biosensors combine in a single device a (bio)recognition element (i) and an electrical transducing element (ii). There are drawbacks: low stability, complex production approaches, high cost and unavailability of some biological targets. Among synthetic (bio)recognition elements, the use of biomimetic material (BM), known as plastic antibodies, is increasing[2]. The transducing element (ii) is responsible to translate the electrical changes (mostly current, resistance and/ or voltage) generated by the localized interaction between the (bio)recognition element and the target compound into a measurable event. The transducing element sends the electrical change occurring on the biosensor via an electrical signal arriving to the external reading apparatus. The apparatus remains a limiting factor for the miniaturization of the complete set-up, increasing costs to the final product
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